Ley williamson



J. DYSON & R. H. WILLIAMSON.

Patented Sept. 24, 1895.

(No Model.) 3 Sheets-Sheet 2.

J. DYSON & R. H. WILLIAMSON. MOLD FOR CASTING SCREWS. N0. 54 ,379.Patented Sept. 24, 1895.

ilsir'rao STATES LYNE, ENGLAND.

MOLD FOR CASTING SCREWS.

SPECIFICATION forming part of Letters Patent No. 546,879, datedSeptember 24, 1895.

Application filed January 10, 1894:. Serial No. 496,421. (No model.)

To aZZ whom it may concern:

Be it known that we, JAMES DYSON, a resident of Good Hope Mill, andRICHARD HAR- LEY WILLIAMSON, a resident of 21 Victoria Street,Ashton-under-Lyne, county of Lancaster, England, subjects of the Queenof Great Britain and Ireland, have invented a Mold for Casting Screws,of which the following is a specification.

This invention relates to an improved mold or chill for casting theribbon-shaped vanes or blades of Archimedean screws.

In the accompanying drawings, Figure 1 is a side elevation of thecomplete screw, the blades of which are formed by this invention. Fig. 2is a sectional view of Fig. 1, showing an end of the screw. Fig. 3 is afront elevation of the mold. Fig. 4 is a plan with the top part removed.Fig. 5 is a perspective view of the lower section of the mold, and Figs.6 and 7 are perspective views of the screw-sections produced by themold.

The blade of the screw is built up of sections, which engage with eachother at the ends, and also engage with one or more flats on the centralshaft by means of straight edges formed on the inner edges of thesections forming the blade, as set forth in our United States Patent No.525,194, dated August 29, 1894. For casting the said sections we employan iron mold or chill. (Shown in Figs. 3, 4, and 5.) The mold is in twoparts a and b, the adjacent contact surfaces of which are formed as ascrew. Each of the parts a and b is so hollowed out in its interior thatwhen the mold is closed by screwing the top part a, down on the lowerpart b the internal cavity corresponds to one of the sections of theblade of the screw. Of the said cavity, one half is formed by the upperpart a and the other half by the lower part b, as indicated bydottedlines at d in Fig. 3. The central part c is left solid, so as to form acore corresponding to the central shaft.

The longitudinal surfaces 70 joining the two halves of the mold areundercut, and it is therefore necessary to give a twisting or screwingmotion to the top section when putting the mold together. Thisundercutting insures perfect registering of the molds and to a certainextent prevents the upper section rising when the metal is poured in.The two halves of the mold are then secured by turning down the handlese, so as to engage with the tongues f.

To cast a section of the blade the mold is closed and laid on its sideand the metal is poured through the casting-hole g, which is placedabout the center of the length of the section to be cast, so that themetal may run toward both ends of the mold at the same time. Aftercasting, the mold is opened by disengaging the handles 6 and screwingoff the top part a, when the cast section may be removed from the lowerpart of the mold.

We claim as our invention- A two-part mold or chill, consisting of twoparts a and I), having helical contact surfaces, undercut jointingsurfaces and a central projection c for casting an entire convolution ofArchimedean screw blade, substantially as set forth.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

JAMES DYSON. RICHARD HARLEY WILLIAMSON.

Witnesses:

JOSEPH BENTON, JOHN HALL.

